Radio Frequency Identification (RFID) systems have been proposed for the tracking of medical item supplies in hospitals and the entire medical item supply chain. Such systems typically involve one or more readers and many RFID tags, each of which is associated with, such as attached to, items being monitored or tracked. In the case of pharmaceuticals, single-use medical devices, and implantable medical devices, RFID tags are typically affixed to or made part of the pharmaceutical containers, e.g., medicine bottle, or medical device container, e.g., disposable packaging for the stent or orthopedic implant. An advantage of RFID tags is that they are stand-off readable, i.e., readable at a distance without a requirement for contact or a direct line of sight path between the reader and the tag.
RFID tags take the form of integrated circuits, with associated antennas, that encode unique serial numbers. The reader can be in a fixed location or mobile with an operator, and items with RFID tags are detected when they enter or leave the electromagnetic field of the reader. For example, RFID readers are often placed at multiple, distributed locations associated within a supply chain in order to monitor the items as they pass through manufacturing, transportation, distribution, storage, to consumption. Each reader captures the RFID tag serial numbers of each item as it enters the reader's interrogation field, and data collected from all readers facilitate item tracking over time, through and within the chain.
Typically, the RFID tags are associated with medical items by affixing them to the medical item packaging. In this way, by tracking the RFID tag, the medical item is tracked in and between the hospital or distribution center or manufacturer.
Such RFID tagged medical items can be stored in storage devices, such as cabinets, that automatically scan the RFID-tagged items contained in the storage devices. In some examples, medical cabinets are provided with RFID reader antennas that are periodically moved or scanned over the length of the cabinets to enable the RFID readers to scan for RFID tags on medical item packages in the storage cabinets. This antenna scanning facilitates detection of the tags regardless of orientation within the cabinets or proximity to other RFID tags. In other examples, stationary antennas are used, when scanning is not required antenna arrays are used.